sorry, I'm doing this on my phone now or I would post some pics. An early LA 360 damper will have a raised oblong weight in front of the main round body of it, late LA 360 and Mag 5.9 will have a deep recess on one side of the round damper ring. If the engine had either as delivered you need an offset weighted converter too.

From the pic you posted it looks like that weight is an initial neutral balancing weight on the outside circumference. But again, I am in my phone. I want to say my offset converter used about a 1" by 3" long weight that was almost as thick as the pads that the flex plate bolts go into.

Sounds to me like you just need to verify what if any external balance you need and get the right converter or offset weight b&m flexplate.